{
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\begin{tabular}{l*{2}{c}}
\hline\hline
                    &\multicolumn{1}{c}{\specialcell{\;\;\;\; Arsenic \\ contamination \\ \;\;\;\; (WHO \\ \;\; threshold)}}&\multicolumn{1}{c}{\specialcell{\;\;\;\;\;\; Fecal \\ contamination}}\\\cmidrule(lr){2-2}\cmidrule(lr){3-3}
                    &\multicolumn{1}{c}{(1)}   &\multicolumn{1}{c}{(2)}   \\
\hline
Wells installed per household&      -9.654***&      -5.005*  \\
                    &     (3.281)   &     (2.756)   \\
\hline
First stage F-statistic&        93.5   &        93.5   \\
R$^2$               &        0.03   &        0.04   \\
N                   &        6051   &        6051   \\
\hline\hline
\end{tabular}
}
